What would a mother do not do for the good of her little ones? The devotion of the elephants who do not let go of a sole, the courage of the bears which protect them against the violence of the males, the selflessness of the female dolphins to teach them to swim … to say nothing of the care sometimes taken throughout of their lives by sapian mothers.
However, in this little game, the mother Orca holds a special place. Its attachment appears without limit. We remember the images of Tahlequah which, for seventeen days, in August 2018, swam by carrying the body of her dead baby on her head, depriving himself of any diet. A published study Tuesday, in Current Biology , has just shown, for the first time, that this sense of sacrifice continued in adulthood with their sons.
For more than ten years already, researchers who scrutinize the fragile colony of the residents of the South, along the west coast of the United States and Canada, found that adult males did not stop taking advantage of devotion kindergarten. Not happy to guide them to the right fishing areas, they give in part of their own catches. “Eat, my son!” Because it is the males who take advantage of most of these generosity. Michael Weiss, research director at the Center for Whale Research, in the American State of Washington, who piloted the study, explains it by the social structure of the species – divided into several groups – and by his biology: ” First, young males reproduce outside their group, while females keep their young with them. So supporting males does not impose new mouths to feed. In addition, the reproductive success of males increases with Age. So it’s a paying investment. “
decrease in reproductive success
An investment: There is actually the originality of this article. “The mother-child relationships that last the whole life are frequent, insists the primatologist Elise Huchard (CNRS, Montpellier), which quotes chimpanzees, bonobos but also hyenas. What is very new is that these maternal influences are expensive. “Michael Weiss’s team took advantage of individual data scrupulously collected for forty years. Each birth is postponed there, as well as each death. She was able to demonstrate that the maintenance of a young male led a mother to lose 50 % chance of having a little year given. A second male, an additional 50 % … “We expected to find a cost but not as high,” says the researcher.
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